Valvetrain breakage?
Thread Starter
Burning Brakes
Joined: Oct 2004
Posts: 792
Likes: 19
From: ME
Valvetrain breakage?
Hey guys,
Trying to diagnose this problem with my little brother. Stock 2000 Camaro SS Just modified last week- put an LS6 intake on there. Ran normally, but occasionally rough idle then goes away after 10 seconds. Ran at the dragway one run (13.7 @106, tons of wheelspin), then in staging lanes heard ticking noise, pulled out of lanes and listened more. Then blipped the throttle a little and SNAP something broke drivers side of engine, idle down to 300-400 Rpm very rough and Shut engine off (didn't stall). So far we have removed the intake and valve covers - Pushrods all are ok. Rockers all ok. Valves all are there. Springs are all not broken. Compression test (motor was cold) showed 160-190psi, so, that was ok. SES light did come on, but couldn't read codes - no scanner. Any ideas? Just weird, because this car isn't driven hard or modified. Heard my fair share of bent pushrods, and stock lifter issues. ... Can't figure this one out. I'm thinking probably a coil or two failed?
Any help AT ALL would be appreciated! Thanks dudes.
Trying to diagnose this problem with my little brother. Stock 2000 Camaro SS Just modified last week- put an LS6 intake on there. Ran normally, but occasionally rough idle then goes away after 10 seconds. Ran at the dragway one run (13.7 @106, tons of wheelspin), then in staging lanes heard ticking noise, pulled out of lanes and listened more. Then blipped the throttle a little and SNAP something broke drivers side of engine, idle down to 300-400 Rpm very rough and Shut engine off (didn't stall). So far we have removed the intake and valve covers - Pushrods all are ok. Rockers all ok. Valves all are there. Springs are all not broken. Compression test (motor was cold) showed 160-190psi, so, that was ok. SES light did come on, but couldn't read codes - no scanner. Any ideas? Just weird, because this car isn't driven hard or modified. Heard my fair share of bent pushrods, and stock lifter issues. ... Can't figure this one out. I'm thinking probably a coil or two failed?
Any help AT ALL would be appreciated! Thanks dudes.
Thread Starter
Burning Brakes
Joined: Oct 2004
Posts: 792
Likes: 19
From: ME
Would it be easy to tell if there were rollers missing from a rocker? We've had them all off and didn't notice anything unusual about the bearings. We did the compression test with the valve covers off, and all the rockers moved the same amount....
We were wondering, These are hydraulic lifters, if we had a bad lifter wouldnt it be obvious that it wasn't pumping up? like maybe being able to feel lash or be able to push down on the pushrod? It seems that there is zero lash like normal on all the rockers.
Bear with me, we're learning here.... Never diagnosed Pushrod V8 noises before.
We were wondering, These are hydraulic lifters, if we had a bad lifter wouldnt it be obvious that it wasn't pumping up? like maybe being able to feel lash or be able to push down on the pushrod? It seems that there is zero lash like normal on all the rockers.
Bear with me, we're learning here.... Never diagnosed Pushrod V8 noises before.
Safety Car
Joined: Sep 2003
Posts: 3,558
Likes: 2
From: Cape Coral FL
If not driven hard, what were you doing at the dragstrip? 13.7 on a stock SS camaro is a pretty good time, so you weren't granny shifting...
Is your valvetrain stock? From what you are describing is either a broken spring, or one of the rockers spit the bearings as suggested above. There is a C-clip on either side of the rocker. On the stock ones it isn't uncommon for the clip to either break, or pop off causing the bearings to fall out.
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Here is one thing I would also look at.
Since you changed the intake manifold, check your spark plug wires. Check they are all on fully, and also ohm them out. The ticking could be an arc. Check the spark plugs for cracks in the porcelin. If that fails try the things below.
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Take all the rockers off. Take all the pushrods out. Inspect the ball ends for damage. Lay them on a piece of glass and roll them. They should all roll evenly.
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Inspect the roller rockers very carefully. The c-clips should all be there and there should be no slop on the trunion.
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With the rockers off, get your face in the springs and really inspect each spring thoroughly.
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Also as suggested above, drain the oil and inspect it for debris, needle bearings, etc.
Is your valvetrain stock? From what you are describing is either a broken spring, or one of the rockers spit the bearings as suggested above. There is a C-clip on either side of the rocker. On the stock ones it isn't uncommon for the clip to either break, or pop off causing the bearings to fall out.
---
Here is one thing I would also look at.
Since you changed the intake manifold, check your spark plug wires. Check they are all on fully, and also ohm them out. The ticking could be an arc. Check the spark plugs for cracks in the porcelin. If that fails try the things below.
---
Take all the rockers off. Take all the pushrods out. Inspect the ball ends for damage. Lay them on a piece of glass and roll them. They should all roll evenly.
---
Inspect the roller rockers very carefully. The c-clips should all be there and there should be no slop on the trunion.
---
With the rockers off, get your face in the springs and really inspect each spring thoroughly.
---
Also as suggested above, drain the oil and inspect it for debris, needle bearings, etc.
Thread Starter
Burning Brakes
Joined: Oct 2004
Posts: 792
Likes: 19
From: ME
Thank you so much for your advice! We're about to do a much more thorough check on the valvetrain and etc. Really thinking now that this motor has a bad lifter(s?). Oh well. We'll tear it up if we have to and then we'll have all kinds of experience to look back on!
